Just 16 seconds into the Lakers battle against the Houston Rockets, Howard collected his own miss to hit the milestone.
Howard hit 9,000 at 27 years and 130 days old. Wilt Chamberlain accomplished the same feat at the age of 27 and 144 days. Bill Russell did it in 27 years 357 days.
Heading into the game Wednesday, Howard had 927 rebounds on the season at 12.4 a game.
Howard is in his ninth season after spending his first eight in Orlando with the Magic.
His career high on the glass was during the 2011-12 season, when he averaged 14.5 rebounds a game.